Spraying of insecticides, Herbicides, oils and liquid fertilizers for horticultural and agricultural applications

ABSTRACT

Grower experience, with poor disease control of grape vines has suggested that, despite overspraying, actual spray coverage was poor, failing to penetrate the dense outer foliage, so that parts of the tree, particularly the top, were inadequately sprayed. Consequently, there was a requirement to ensure that spraying materials were deposited more efficiently and effectively upon targeted foliage, thereby reducing the volume of liquid carrier and therefore the amount of chemical required for a particular crop. This problem has been overcome by directing two fan-driven spray units (14) upward and into the foliage canopy, so as to displace the leaves in upward and outward directions, in co-operation with at least one further spray unit (16) downwardly directed, so as to spray into and partly through the canopy. The spray units are mounted on an inverted U-frame (21), which in turn is mounted on a mobile chassis or tractor (10) for transport through the crop area. For preference, two upper spray units (16) are employed, with a further option for a fifth spray unit (17), adjacent the apex (22) of the inverted U-frame (21). Multiple frames (21) may also be exploited, by suspension from an overhead boom (12). The operation is enhanced by automatic sensing and control, regulating the distance of the spray units (15, 16, 17) from the canopy, adjusting the spray rate to the canopy volume, the surface area of the leaves and produce, careful adjustment of the positions and directions of the spray units (15, 16, 17), and relating the speed of the spraying equipment to the volume of liquid sprayed. Liquids sprayed include insecticides, herbicides, oils and fertilisers.

This invention relates both to a spray method and also to spray means,useful for spraying insecticides, herbicides, oils and liquidfertilisers for horticultural and agricultural applications.

Generally the spraying rates of insecticides, herbicides and liquidfertilisers are determined by unit area of land on which it is applied(for example liters per hectare). These rates are normally recommendedby the manufacturers.

Due to different soil types and qualities, however, the number ofplants, vines and/or fruit trees etc per hectare can significantly vary.The variation in the number of plants per hectare is generally effectedby altering the row spacing between rows of plants. Ideally thereforethe spraying rates should be determined by the number of plants perhectare and/or the plant canopy sizes and/or volumes and/or the leaf andproduce surface area.

Tests are referred to hereunder however which refer to the number ofliters per hectare in accordance with convention, but this inventionseeks amongst other things to provide a spraying method wherein the sizeof a canopy of a plant, more particularly a grape vine, can bedetermined, for two reasons, firstly that the spray heads are maintainedat an optimum distance away from foliage and secondly that the sprayrate needs to be varied and increased for large canopies, quiteindependently from the number of hectares. In order to achieve this,there is disclosed in this specification a concept wherein optical orsonar sensors can continuously measure canopy size, and means wherebythe spraying pressure can be regulated so that the spraying flow ratecan be proportional to the canopy size, reckoned as volume.

One of the most disturbing aspects of spraying, as currently conductedin agriculture, is the excessive use of insecticides, herbicides andother chemicals. This has been recognised in environmental regulations,and policies are being enforced worldwide in order to minimise water andsoil contamination due to off target spray losses. This inventiontherefore has as a main object the provision of means and methodswhereby there is less overspray and therefore less usage of chemicalsthan heretofore, resulting not only in an environmental saving but alsoa very considerable saving in expense.

In one typical embodiment, use is made of a pair of curved arms ofpincer-like or horseshoe shape, hinged above the canopy and extendingdownwardly over each side. Desirably the arms are angled at hinge pointsabove the canopy, and fan spraying heads are mounted on the arms whichcan be adjusted up or down, the arms and also rotated to blow into thecanopy at a desired angle, both backward and forward with respect todirection of travel and also up and down. This particular configurationof arms was arrived at after many experiments and was chosen for itssimplicity of control. A pincer or horseshoe arrangement has theinherent advantage that adjustments to the extension of the pincerresults in an approximately equidistant movement of spray heads attachedto the arms from the foliage at most points along the arms. As a result,this particular configuration maintains the required distance betweenthe foliage and the spray heads for most canopy cross sectional shapes.This aspect was noted by the Applicant as being an opportunity toimplement this arrangement for spraying which would result in anextremely simplified control mechanism as compared with the prior art.The simplified control mechanism for adjusting the spray heads fordifferent sized canopies of foliage results in a significant cost savingin the provision of an adjustable spraying system as compared with theprior art.

PRIOR ART

Applicant has made extensive searches of both Australian and overseasdatabanks but very little has been disclosed by those searches which isrelevant to the present invention. By far the closest reference was theAustralian Patent Application 40665/95 in the name of Technion Researchand Development Foundation Ltd of Israel, the inventor being GedalyahuManor and Amos Geva. The reader's attention is drawn to FIG. 14 of thedrawings of that specification wherein spray was imparted over the top,sides and partially into the interior of the canopy, and on page 9,second full paragraph, there is a brief description of how "the flexibleduct can be bent into various shapes around the contour of therespective tree or plant".

However, the closest prior art which has been discovered by theApplicant is a report in the Journal of Agricultural Engineering (198532, 291-310). There was a report in the 1985 British Society forResearch in Agricultural Engineering and the report was from theDepartment of Agriculture, Research Centre, PO Box 411, Loxton, SouthAustralia 5333. A contributor to the work was Geoffrey O. Furness, andthey reported having achieved a spray coverage with a multi-head sprayerat 650 liters per hectare using converging air jets as compared withregard to uniformity of coverage only, with that from an oscillatingboom at 10,000 liters per hectare and that from an air blaster 8,000liters per hectare, using a percentage spray cover rating system. With amulti-head sprayer, almost 90% of the upper and 50% of the under leafsurfaces has a droplet number of 500 per cm² or greater.

This report was based on grower experience with poor disease control ofgrape vines suggesting that spray coverage was poor, particularly in thecentre of a vine. The report cited with approval a report by MessrsCarman and Jebbson wherein they suggested that "the spray penetrates thedense outer foliage poorly, and, as a result, parts of the tree,particularly the tree top, are inadequately sprayed". Mr Furnessobserved that "the air blaster is essentially unidirectional, causingleaves to bend back against one another, thereby creating a wall offoliage not readily penetrated by the spray stream". The report includeda reference to the development of a simple sprayer which moves largevolumes of air and eliminates the unidirectional, rapidly divergingnature of air stream generated by an air blast sprayer, and therebyprovides a considerable improvement in sprayer performance. The sprayerreported was a multihead machine which allowed air convergence onto thetarget and had the important effect of increasing the level ofturbulence. For the spraying of grapevines, Mr Furness disclosed the useof two heads converging in a vertical plane with the lower head aimed45° upwards and the upper head aimed at 45° downwards from above thevine. The spray was directed straight at the vine, that is at 90° of thedirection of the vine row.

Although the Furness development reduced the spray requirements by afactor exceeding 10, air blast sprayers and "turbo miser" sprayers arestill the most commonly used sprayers for grape vines in Australia.

The main object of this invention is to still further improve theefficiency of agricultural spraying such that spray materials are moreefficiently and effectively deposited upon targeted foliage. This hasthe resultant effect of reducing the volume of liquid carrier requiredfor spraying and also reduces the amount of chemical required for aparticular crop as compared with the prior art methods. In a report on aprototype which preceded this invention as now developed and describedherein, but was produced by the Applicant, the University of SouthAustralia indicated that for medium to dense foliage canopies of grapevines, the liquid quantity required using that prototype to give a 95%effective coverage was less than 100 liters per hectare. This of courseis achieved in this invention as it was in the prototype by reducingoverspray, and that in turn has been achieved by displacing the air inthe space within a canopy with two air streams entraining the sprayedmaterials and entering the canopy from opposite sides, andsimultaneously or very quickly thereafter, spraying the outer surface ofthe canopy with further air streams entraining further quantities ofspraying materials. This arrangement appears to limit overspray to anegligible level.

There are however a number of other matters which require carefulconsideration to achieve such results and they include:

a) a need to regulate distance of the fan from the canopy, and that inturn to some extent will depend on the canopy wherein shapes and sizesvary with different species;

b) automatically adjusting the spray rate according to canopy volume;

c) careful adjustment of the positions and directions of the sprayheads;

d) relating the speed of the spraying equipment to the volume of theliquid which is being sprayed; and

e) adjustment of the spraying rate according to the surface area of theleaf and produce to be sprayed.

The above-referred to achievement of less than 100 liters per hectarewas achieved with an over row tractor spraying a row of grape vines atapproximately 9 km/h. Whilst the achievements of this invention havebeen measured during spraying operations involving grape vines, itshould be noted that the invention contained herein and its consequentadvantages are equally applicable to other crops including citrus, stonefruit, apple and pear crops and even cotton crops. Virtually any type ofcrop which is farmed in rows can take advantage of the improvedefficiency of spraying made available by this invention. In addition, itshould also be noted that the improved spray distribution resulting fromthis invention also results in the increased viability of using oils ascarriers during spraying operations. Oils are sometimes used as acarrier during spraying operations for their inherent advantage ofremaining upon foliage even if the foliage is subjected to rain soonafter spraying. The improved effectiveness in applying materials totarget foliage evenly and on both sides of the leaf increases theviability of greater use of oil carriers as compared with prior artspraying systems.

BRIEF SUMMARY OF THE INVENTION

In this invention the method of spraying a plant having a foliage canopyincludes spraying with two lower sprays up into the space within thecanopy, the lower sprays being located at each side of the canopy,spraying with two upper sprays downwardly over the outside of thecanopy, and spraying with a fifth spray directly over the centre of thecanopy but rearwardly of the other spray heads, all sprays beingassociated with air streams imparted by an impeller or impellers, andtraversing the spray equipment over the canopy.

The equipment for the spraying requires a mobile frame which is fastenedto an over row tractor, and having two upwardly directed spray headswhich direct an air flow and entrained spray upwardly into the spacewithin the canopy, two downwardly directed spray heads which direct anair stream and entrained spray over the sides of the canopy and a fifthspray head which directs spray downwardly over the top of the canopy,the air streams having sufficient force and flow rate to displace airfrom within the canopy, and all air streams being directed towards aspace within the canopy, thereby converging and co-acting with oneanother to provide a high degree of turbulence which however iscontained within, or very close to, the outer surface of the canopy.

As previously mentioned, the preferred configuration for the arms of thespraying equipment is a horseshoe or pincer arrangement. Thisconfiguration enables the spraying assembly to be adjusted for varyingsized canopies with an extremely simple adjustment mechanism as comparedwith the prior art. This mechanism may be adjusted by hand or may beincluded as part of an automatic control system comprising a foliagedetection means to enable automatic and controlled adjustment of thespraying arms, and hence the distance between the spray heads and thefoliage to be sprayed. Additionally, the adjustment mechanism may beimplemented by various means. In the preferred embodiment the adjustmentmeans for the pincer arrangement of spraying arms comprises apiston/cylinder assembly, however this could equally be effected by anarrangement of intermeshing gears or some other similar mechanism whilstretaining its simplicity of control.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment is described with reference to and isillustrated in the accompanying drawings in which:

FIG. 1 is a diagrammatic side elevation of an over row tractor providedwith a plurality of spray heads carried on a mobile frame which isaffixed to the over row tractor;

FIG. 2a shows a basic form of spraying sub-assembly for one full plantrow wherein all adjustments are made by hand;

FIG. 2b is a fragmentary side elevation of a lower spray headillustrating a swivel clamp adjustment of the spray head; and

FIG. 2c is a section taken on line 2c--2c of FIG. 2a.

FIG. 3 is a representation of three spraying sub-assemblies carried on abridge as viewed from the front of an over row tractor, FIG. 3 being afront elevation of the side elevation shown in FIG. 1;

FIG. 4 is a fragmentary view which illustrates the suspension of aspraying sub-assembly from the mobile frame shown best in FIG. 3;

FIG. 5a is a fragmentary side elevation of a lower spray head andillustrating control of the "wrist movement" of the spray head; and

FIG. 5b is a section taken on line 5b--5b of FIG. 5a.

FIG. 6 shows the independent processes which form the spraying system.

FIG. 7 describes the Operator Control Process

FIG. 8 describes the Flow Rate Control Process

FIG. 9 describes the Fan Position Control Process

FIG. 10 describes the Row Spacing Control Process

FIG. 11 describes the Fan Motor Control Process

FIG. 12 describes the Boom Control Process

FIG. 13 describes the Row Spray Control Process

FIG. 14 describes the condition Monitoring & Control Process.

Reference is made first to FIG. 1 which shows an over row tractor 10 asusually employed for pruning or harvesting a row of grape vines, andhaving on it a container 11 of materials to be sprayed over a row ofgrape vines. A mobile frame 12 is carried on the over row tractor, andFIG. 1 illustrates how the mobile frame 12 can carry on it a pluralityof spraying sub-assemblies 13, two being seen in FIG. 1 one behind theother, this being necessary because when this invention is used on cropswith either narrow raw spacings or large canopies, the sprayingsub-assemblies 13 will overlap and hence they need to be staggered ifthree rows of grape vines are to be sprayed simultaneously. As seen alsoin FIG. 1, each frame sub-assembly also includes two side upper sprayheads 16 and one central upper spray head 17 carried on arms 18.

Vertical movement of the entire spraying sub-assemblies 13 is achievedby inbuilt hydraulics on the over row tractor 10, and further hydrauliccylinders are used for other functions, for example FIG. 1 showing ahydraulic piston/cylinder assembly 20 which will raise or lower thecentral upper spray head 17.

FIG. 2a illustrates a very basic type of spraying sub-assembly 13wherein all adjustments are made by hand. There are two arms 21 ofcircular section tubing which are shown pivoted about a single pivot 22,and the space apart of the lower spray heads 14 is achieved by clampingthe outer sleeves 23 to a base plate 24 to fasten the sleeves 23adjustably for position, by bolts 25 being movable in arcuate slots 26.The central spray head 17 is shown only in dashed lines because quitereasonable results can be achieved with the arrangements shown, althoughthose results do not compare with the results which are achieved withthe preferred embodiment which is illustrated more particularly in theremaining drawings.

Whilst a high level of flexibility is achieved by the adjustment of thespray heads 14 and 16 towards and away from the canopy 35, a furtheradjustment is still required.

FIGS. 2b and 2c illustrate a basic swivel clamp arrangement for a sprayhead mounted on an arm 21. The spray head comprises an electric motor 46which is directly coupled to a fan 47. The fan 47 induces a flow of airwhich in turn entrains spray from nozzles 48. A further adjustment isrequired to vary the direction of air and spray impelled by fan 47. Thisis achieved by the swivel clamp 49 and 52 and adjustment is effected byloosening the nuts 53, repositioning the spray head and tightening thebolts 53. This enables the spray heads be adjusted to the desired anglein relation to the foliage and the direction of travel.

FIG. 3 shows the mobile frame 12 being the form of a bridge which isalso shown in FIG. 1, and each spraying sub-assembly 13 includes lowerspray heads 14, upper spray heads 16 and an upper central spray headwhich is not illustrated in FIG. 3 for the purpose of clarity of thedrawing. The spray heads are carried on the respective arms 21 asdescribed previously, and arm 21 is illustrated as being curved todiverge downwardly away from the other arm of its pair at its upper endand converge downwardly towards the other arm of its pair at the lowerends of the arms to define a horseshoe shape, the upper spray head 16being clamped to the upper ends of the arms 21 and the lower spray heads14 to the lower ends.

FIG. 3 illustrates three suspension means all designated 30 from thebottom of the mobile frame 12 which suspend the respective sprayingsub-assemblies 13, and FIG. 3 also shows how the ends of the mobileframe 12 are provided with guides 31 which guide slides 32 for movementtowards or away from the ends of the mobile frame 12, and the two outerspraying sub-assemblies 13 depend from the slides 32 through thesuspension means 30 while the inner one is fixed with respect to themobile frame 12. Thus the hydraulic piston/cylinder assemblies 33readily adjust the positions of the two outer spraying sub-assemblies 13to vary those positions as the spacing between the rows of vines 34varies, sometimes in the same traverse of the over row tractor 10 andsometimes as the over row tractor 10 traverses alternative rows of vinesof different species, for example.

Not only does the space between the rows of vines 34 vary, but thecanopies 35 also vary dimensionally, and FIG. 3 and FIG. 4 bothillustrate a linkage mechanism 36 wherein a further hydraulicpiston/cylinder assembly 37 can adjust each respective pair of arms 21in opening or closing them about pivots 38. The upper end of each arm 21is carried by a bearing block 41 which embodies a respective pivot 38,and each bearing block 41 has an extending lug 42, the lugs 42 beinggenerally parallel and being joined together by a link 43, thearrangement being such that actuation of the hydraulic piston/cylinderassembly 37 will cause the arms to swivel further apart or closertogether about their respective pivots 38.

In addition to the adjustment which can be achieved of the spacingbetween the adjacent spraying sub-assemblies 13, the adjustment of thespray heads 14 and 16 towards and away from the canopies 35 and theability to reposition any or all of the upper spray heads 16 and thelower spray heads 14 on the arms 21, a further adjustment is required.

FIGS. 5a and 5b detail a fragmentary side elevation of a lower sprayhead and illustrate control of the "wrist movement". The spray headcomprises an electric motor 46 which is direct coupled to a fan 47 whichwill induce a flow of air which will in turn entrain spray from nozzles48. A wrist type adjustment is required to vary the direction of the airand spray being impelled by fans 47 about the axis A--A through a swivelbearing arrangement 49 and 49a, and this is achieved by a hydraulicpiston/cylinder assembly 50, herein called the "wrist adjustmentcylinder". Further to that adjustment, there is a requirement foradjusting the spray heads 14, 16 and 17 to be at 90° of the direction oftravel, or to be inclined thereto and that is achieved by adjustment ofthe clamp 52, but since that adjustment is only required very rarely, itis achieved by the relaxing and re-tightening of the clamping bolts 53.It is believed that the best results can be achieved by having the lowerspray heads 14 pointing in the forward direction, and the upper sprayheads 16 in a slightly rearward direction, while the upper central sprayhead 17 is located further rearward. This enables a displacement of airfrom the space within the canopy 35 before the outside of the canopy issubjected to spray coming from the upper spray heads. Since atapproximately 9 km/h to 12 km/h, the sprayed area of a vine can betraversed in a little over 2 seconds of time, there is little chance foroverspray to develop when the canopy is subject to at least four andpossibly five streams of air with entrained spray, and the leaves of thecanopy itself are subject to a lot of turbulence because of theturbulent flow of air and spray around them, and that turbulence alsoassists in limiting over spray.

As said above, it is desirable to carefully adjust the distance betweenthe spray heads 14, 16 and 17 and the outer surface of the canopy, adistance of about 300 mm being regarded as very satisfactory.Furthermore, the arms 21 being of circular section tube enable notmerely rotational but also sliding movement of the spray heads up anddown the arms to best suit the conditions which are encountered innormal vineyard spraying.

The mobile frame 12 in the embodiment of FIGS. 3 and 4 is in effect abridge which is centrally secured to the over row tractor 10 by securingbolts 56 (as detailed in FIG. 1), so that dismantling and removal orreassembling of the entire spraying equipment can be readily and simplyachieved.

As shown, the air is being impelled by means of a separate fan and motorassembly on each spray head, but clearly use can be made on a centralblower to blow air through ducts.

The method of using the equipment described above comprises primarilyoperating the two lower fans to direct the sprays entrained in the twolower air streams created by those fans to converge upwardly into alocality within the canopy from both sides with sufficient energy todisplace the air from the canopy space and also to displace leaves fromwithin the canopy in upward and outward directions. The upper fans areoperated to cover the canopy with spray entrained in the upper airstreams, and all the air streams are directed towards the space withinthe canopy so that they co-act and create a high degree of turbulence.This method of spraying and the resulting high degree of turbulencecreated has been found to significantly improve the effectiveness of thespraying process by providing a superior coverage of the target foliagewith sprayed materials as compared with prior art systems known to theApplicant. Improved targeting of the spray materials to the targetfoliage results in a significant reduction in overspray. The overallresult of these improvements is a dramatic reduction in the requiredspray materials for a given size of crop as compared with prior artsystems which in turn results in beneficial financial and environmentaleffects.

It is thought to be desirable to first displace the air within the spacebeneath the canopy with spray before the upper sprays envelope the outersurface of the canopy, since not only is the wetting of the innersurfaces of leaves improved by the flow of air from the lower sprayheads into the space beneath the canopy, without the force of air fromthe upper spray heads inhibiting free flow of air through the canopyfrom beneath, but also the degree of turbulence, both inside and outsidethe canopy is increased. In the event that the spraying takes place latein the season but before picking, the inwardly directed sprays frombeneath the canopy will also impinge upon the fruit, and thereby improveprotection against the various diseases such as downy mildew.

The equipment described above can be enhanced by various accessories.For example, the or each spraying sub-assembly may be provided with anoverhanging deflector, effective to return upwardly moving droplets backto a canopy. Still further, a partly surrounding shroud can overlie thetop and sides of the canopy or even separate shrouds for each individualfan and spray head assembly. In addition, although the adjustment of theangular positioning of the fans is detailed in this specification asbeing manual, enhancement of this facility to provide automaticadjustment of the angular positioning in accordance with the expansionor contraction of the spray sub-assemblies could be easily implemented.

The following is a brief summary of the electronic control system whichis embodied in this invention to give control of many features of thespraying system.

DESCRIPTION OF FUNCTIONAL MODEL OF SPRAYING SYSTEM

The spraying system conceptually comprises eight independent processesthat execute simultaneously. These eight independent processes areindicated in FIG. 6 as "Operator Control Process", "Flow Rate ControlProcess", "Fan Position Control Process", "Row Spacing Control Process","Fan Motor Control Process", "Boom Control Process", "Row Spray ControlProcess" and "Condition Monitoring & Control Process". The subsequentFIGS. (7 to 14) detail the functions of each of these processes. Each ofthese processes will execute indefinitely as the operation of thespraying system is intended to occur indefinitely and will only behalted in the event of an operator shutting down the system or in theevent of a system failure detected by the "Condition Monitoring &Control Process".

Each of the main processes communicate between functions via the use ofmessages (detailed by the use of round cornered boxes) which may havemultiple sources and/or destinations. Messages may trigger a function tostart execution and/or it may be the source of information which thereceiving function will use at a later time. Indefinite loops that occurby default without evaluation of any criteria are annotated with theword "Loop".

As it would be appreciated by those skilled in the art, the physicalarchitecture of the spraying system could be implemented with a varietyof computational equipment configurations available from manufacturersof electronic control systems. The functional model of the sprayingsystem described below is independent of any particular physicalarchitecture and provides sufficient detail to a person skilled in theart to perform the invention with any physical architecture of theirchoice.

Each of the main processes detailed in FIG. 6 comprises its owninitialisation stage wherein default parameters are implemented for thatparticular process. Upon the starting of the spraying system, each ofthese processes is initialised into an operational state and cancontinue execution with its default settings.

However, the "Operator Control Process" enables an operator toindividually control each of the main processes thereby enabling theoperator to effect changes to the default parameter settings.

The "Operator Control Process" as detailed in FIG. 7 comprises its owninitialisation and default parameter setup stage. Subsequent to theinitialisation stage the operator is presented with a menu of items fromwhich the operator can choose a particular aspect of the spraying systemthat he wishes to adjust or control. The selection of the items from themenu system is most likely to be implemented by means of a touchsensitive liquid crystal display.

If the operator wishes to alter or adjust the currently active fanmotors, selecting this particular item from the menu system causesexecution to follow the path designated "p1". The function "selectactive fan motors" enables the operator to activate or de-activateindividual fan motors on the spraying sub-assembly. Upon selecting a newconfiguration of active fan motors, a message is passed from thisfunction to the "Fan Motor Control Process" designated by "A".

If the operator wishes to adjust the angular positioning of individualfan motors, selecting this item from the menu system causes execution tofollow the path designated "p2". The adjustment of individual fan motorangular positions is performed by the operator viewing the individualfan motor as he manipulates the position controls for the fan motor.Upon completion of this function control is returned to the "select menuitem function". In the preferred embodiment, the controls for angularpositioning adjustments are common across sets of fans, and has beenimplemented such that all lower fans are commonly controlled and allmiddle fans also share a common control. In this way, the operator needsonly to make a single adjustment for each set of fans.

The operator may choose to alter the current fan position adjustmentmode from the default mode and upon so doing execution is directionalong the path designated "p3". This particular function enables theoperator to select either a manual or automatic fan position adjustmentmode. The manual mode for fan position adjustment enables the operatorto manually select an appropriate fan position in relation to thefoliage to be sprayed. Having selected the manual mode the operator maymake subsequent changes to the fan positions in relation to the foliageto be sprayed by executing this function at a later stage and making theappropriate manual adjustment. However, if the operator chooses theautomatic mode, the "Fan Position Control Process" is activated andmaintains the fan position relative to the foliage to be sprayed byautomatic control. Depending upon the adjustment mode selected by theoperator a message or messages are sent to the "Fan Position ControlProcess" as designated by "B". Again, upon completion of this functioncontrol is returned to the "Select menu item function".

A diagnostic mode is available to the operator and upon selection ofthis mode execution is directed along the path designated "p4". Thediagnostic mode enables the operator to view and monitor results fromvarious measurement systems and transducers placed throughout thespraying and electrical system. Upon completion of this function controlis again returned to the menu item selection function.

The operator may also choose to alter the spray operating mode and uponso doing causes execution to be directed along the path designated "p5".The operator may choose one of four spray operating modes comprisingeither a fully manual mode wherein a fluid pressure regulator isadjusted by hand, a constant flow rate, a proportional flow rate inrelation to the speed of the vehicle, or a proportional flow rate inrelation to the vehicle speed and the positioning of the spraying arms(hence spraying being proportional to the foliage canopy size). Havingselected a particular mode, a message is sent to the "Flow Rate ControlProcess" designated by "C". If the operator selects a constant flow rateoperating mode then this message will also contain the desired flowrate. Upon completion of this function control will return to the menuitem selection function.

The operator is also provided with control in relation to whichparticular rows are actively spraying at any point in time. If theoperator chooses to make a change in this regard execution is directedalong the path designated by "p6". Upon selecting which particular rowsare to be actively spraying, a message is sent to the "Row Spray ControlProcess" designated by "D". Upon completion of this function control isthen returned to the "Select menu item function".

The operator is provided with the ability to enter an initial liquidvolume contained in the spraying tank and upon selecting this optioncauses execution to be directed along the path designated "p7". If theoperator chooses to enter a value representing the volume of liquidcontained in the spraying tank at the start of spraying operations, thesystem provides an estimate of the remaining liquid in the tank duringoperation of the spraying system. Once again, control is then returnedto the "Select menu item function".

In the preferred embodiment, the two outer spraying sub-assemblies arehinged on the mobile frame enabling these sub-assemblies to be folded orclosed when non-operational. In their closed position, the "booms" restadjacent to the over row tractor enabling ease of transport of thespraying system. The operator is also provided with the ability tomanually control the boom positions and upon electing this option theoperator causes execution to be directed along the path designated by"p8". This particular function enables the operator to open or closeindividual booms. Upon making an appropriate selection, a message issent to the "Boom Control Process" designated by "E". Upon completion ofthe function control is then returned to the "Select menu itemfunction".

The operator is also provided control in relation to the row spacingcontrol mode. Upon requesting a change in this regard execution isdirected along the path designated by "p9". The operator may selecteither a manual or automatic row spacing control mode. Having made aselection an appropriate message is sent to the "Row Spacing ControlProcess" designated by "F". If the operator selects the manual rowspacing control mode he is then provided with the ability to make manualadjustments to the row spacing. Upon completion of this function controlis then returned to the "Select menu item function".

The operator is also provided with the ability to indicate to the systemthe starting and the completion of a row for spraying. In addition theoperator is provided with a shut down facility. In selecting any ofthese options execution is directed along the path designated "p10".Upon selecting from the menu system either the start or complete rowindicator and/or the shut down option, appropriate messages are sent tothe "Fan Motor Control Process", the "Boom Control Process" and the "RowSpray Control Process" designated by "G". Under normal operatingconditions upon initialisation and start of the spraying system the "RowSpray Control Process" default setting is set to spray all three rows,the "Boom Control Process" default setting is set to open both booms andthe "Fan Motor Control Process" defaults to a sequential start up ofeach fan motor on each frame sub-assembly. Upon selecting the start rowindication a message is sent to the "Fan Motor Control Process" toactivate selected fan motors if they are currently not operational. Atthe same time a message is sent to the "Boom Control Process" to openthe booms. Once the fan motors are started and the booms are opened amessage is sent to the "Row Spray Control Process" to open theappropriate row valves enabling fluid flow from the storage tank to theindividual spray outlets. Upon selecting the complete row indicator, amessage is sent to the "Row Spray Control Process" to close all rowvalves thereby stopping all spray heads from spraying and at the sametime a message is sent to the "Boom Control Process" to close bothbooms. Between the completion of one row and the commencement of anotherrow, the fan motors are left running while spraying is discontinued andthe booms are closed. However, upon selecting the shut down option thesame message is sent to the "Row Spray Control Process" and the "BoomControl Process" as is sent for the complete row indication but inaddition a message is also sent to the "Fan Motor Control Process"de-activating all fans. Upon completion of this function control isreturned to the "Select menu item function".

The select menu item function also receives messages from the conditionmonitoring and control process. These messages are to indicate to theoperator alarm conditions and are designated by "J". At any time theoperator can select the alarm monitor and control function therebycausing execution to be directed along the path designated "p11". Thisfunction enables the operator to view more specific details of the alarmmessage from the condition monitoring and control process and tomanually override or cancel the alarm. In either case a message is sentfrom this function to the condition monitoring and control processdesignated by "H". Upon completion of this function control is returnedto the "Select menu item function".

FIG. 8 details the "Flow Rate Control Process". In the preferredembodiment, the flow rate of dispensed materials from the spray heads iscontrolled by means of adjustments to the pressure maintained in theconduit connecting the individual spray heads. The fluid pump whichtransfers the fluid from the storage tank to the spray heads is ahydraulic pump which operates at a predetermined flow rate. The pressurein the conduits is adjusted by means of an electrically controlledpressure regulator which in turn controls the flow rate of the fluidemanating from the spray heads. Upon initialisation of the sprayingsystem the "Flow Rate Control Process" enters an initialisation anddefault parameter setup stage. Upon completion of the initialisationstage the process enters the "Read Incoming Message Buffer" function.This function acts to read any awaiting incoming messages includingmessages from the "Operator Control Process" and flow meter readingsfrom external transducers. The "Flow Rate Control Process" defaults to aconstant flow rate setting and upon the first execution of the readincoming message buffer function if no messages are received from the"Operator Control Process" execution progresses along the pathdesignated "const". Having established a constant flow rate control isreturned once again to the "Read Incoming Message Buffer" function.Again, if no messages have been received from the "Operator ControlProcess", execution is directed along the path designated "no messages".This causes the process to execute the "compare target flow rate toactual rate and perform adjustment" function wherein any adjustmentsrequired are made to the measured flow rate of the fluid to the sprayheads. Upon completion of this function control is then returned to the"read incoming message buffer" function. Assuming that no messages havesubsequently been received from the "Operator Control Process" executionis again directed down the path designated "no messages" wherein atarget flow rate is compared to an actual flow rate as indicated fromtransducers through the flow meter readings messages received by theincoming message buffer. This sequence of events continues until amessage is received from the "Operator Control Process". Messages may besent from the "Operator Control Process" to select an alternate sprayoperating mode. Apart from the constant flow rate mode, the operator mayalso select a proportional flow rate control wherein the flow rate iscontrolled according to the speed of the over row tractor, or aproportional flow rate control mode wherein the flow rate is controlledaccording to both the speed of the over row tractor and the extension orcontraction of the spray arm (and hence the foliage canopy size). If theoperator selects either of these modes execution is directed along theappropriate path either "prop1" or "prop2". Upon completion of thesefunctions a proportional flow rate control system is activated andcontrol is then returned to the "read incoming message buffer" function.Again, whilst no further messages are received from the "OperatorControl Process" execution continues to loop through the "compare targetflow rate to actual rate and perform adjustment" function andadjustments to the flow rate are performed in accordance with the flowmeter readings received from external transducers. In addition to eachthe flow rate control modes identified above, the operator may alsoselect a completely manual mode wherein adjustments to the flow rate aremade by hand. In selecting this option, a message is sent from the"Operator Control Process" to the "Flow Rate Control Process" toeffectively halt the "Flow Rate Control Process" from furtherprocessing. This enables the operator to make manual adjustments to theflow rate which may be required for maintenance or during a diagnosticssession for example. Apart from the completely manual option, the "FlowRate Control Process" continues indefinitely until the spraying systemis completely shut down.

The "Fan Position Control Process" controls the adjustment of thespraying arms to control the distance between the spray heads and thefoliage to be sprayed. Upon initialisation of the spraying system thisprocess enters an initialisation and default parameter setup stage. Uponcompletion of the initialisation stage the process enters the "readincoming message buffer" function. The manual option is the defaultsetting for the "Fan Position Control Process" and upon entering the"read incoming message buffer" function execution of this process haltsand awaits a message to be received from the "Operator Control Process"designated "B". The operator can choose to manually adjust the sprayingarms thereby causing execution to be directed along the path designated"manual". Upon completion of adjusting the fan positioning relative tothe foliage to be sprayed, control is returned to the "read incomingmessage buffer" function. However, if the operator selects the automaticmode, execution is directed along the path designated "automatic" andthe "establish automatic control of fan position" function is executed.Having activated the automatic control system for positioning of thespraying arms, the target position of the spraying arms is compared tothe actual position based upon the canopy size readings passed to the"Fan Position Control Process" from external transducers. Appropriatepositioning adjustments are performed if required. Upon completion ofthese functions control is once again returned to the "read incomingmessage buffer" function. If the automatic mode has been selected andcanopy size readings are received from the external transducers thenprocess execution continues down the path designated "automatic". Thissequence of events will continue until a message is received from the"Operator Control Process" halting the continuance of the automatic modeand selecting the manual positioning mode.

FIG. 10 details the functions of the "Row Spacing Control Process".Again, upon initialisation of the spraying system this process enters aninitialisation and default parameter setup stage. Upon completion ofthis stage the process enters the "Read Incoming Message Buffer"function. This process is analogous in its execution to the "FanPosition Control Process". The "Row Spacing Control Process" controlsthe adjustment of the spraying sub-assemblies to control the distancebetween the spraying sub-assemblies according to the variation in rowspacing of the crop. Upon initialisation of the spraying system thisprocess enters an initialisation and default parameter setup stage. Uponcompletion of the initialisation stage the process enters the "readincoming message buffer" function. The manual option is the defaultsetting for the "Row Spacing Control Process" and upon entering the"read incoming message buffer" function execution of this process haltsand awaits a message to be received from the "Operator Control Process"designated "F". The operator can choose to manually adjust the sprayingsub-assemblies thereby causing execution to be directed along the pathdesignated "manual". Upon completion of adjusting the sub-assembliespositioning relative to the foliage to be sprayed, control is returnedto the "read incoming message buffer" function. However, if the operatorselects the automatic mode, execution is directed along the pathdesignated "automatic" and the "establish automatic control of rowspacing" function is executed. Having activated the automatic controlsystem for positioning of the spraying sub-assemblies, the targetposition of the spraying sub-assemblies is compared to the actualposition based upon the row spacing readings passed to the "Row SpacingControl Process" from external transducers. Appropriate positioningadjustments are performed if required. Upon completion of thesefunctions control is once again returned to the "read incoming messagebuffer". If the automatic mode has been selected and row spacingreadings are received from the external transducers then processexecution continues down the path designated "automatic". This sequenceof events will continue until a message is received from the "OperatorControl Process" halting the continuance of the automatic mode andselecting the manual positioning mode.

FIG. 11 details the function of the "Fan Motor Control Process". Uponstart up of the spraying system the process enters an initialisation anddefault parameter setup stage. Upon completion of this stage the processthen enters an indefinite loop wherein the process reads incomingmessages and either enables or disables fan motors according to thereceived instructions. The "read incoming message buffer" functionreceives messages from either the "Operator Control Process" or thecondition monitoring and control process. Message "A" is received fromthe "Operator Control Process" upon selection by the operator tomanually enable or disable individual fan motors. Message "G" is alsoreceived from the "Operator Control Process" as part of the messagesequence sent from that process as a result of the operator selectingthe shut down option. Message "K" is received from the conditionmonitoring and control process upon alarm activation requiring all fanmotors to be shut down. FIG. 12 details the functions of the "BoomControl Process". Upon initialisation of the spraying system thisprocess enters an initialisation and default parameter setup stage. Uponcompletion of this stage the process enters an indefinite loop whereinincoming messages are received and the booms are either opened or closedaccording to the instructions received by those messages. This processis analogous to the "Fan Motor Control Process". The "read incomingmessage buffer" function receives messages from the "Operator ControlProcess". Message "E" is sent from the "Operator Control Process" uponselection by the operator of the "adjust boom position" function.Message "G" is also received from the "Operator Control Process" and issent as part of the message sequence associated with the operatorselecting the complete row indication and shutdown option.

FIG. 13 details the functions of the "Row Spray Control Process". Uponinitialisation of the spraying system this process enters aninitialisation and default parameter setup stage. Upon completion ofthis stage the process enters an indefinite loop wherein messages arereceived from both the "Operator Control Process" and the conditionmonitoring and control process and the instructions received from thosemessages are effected in either the opening or closing of valves toenable or disable the flow of fluid to the spray heads of a set ofspraying arms. Message "D" is received from the "Operator ControlProcess" upon the operator executing the "select spraying rows"function. Message "G" is also received from the "Operator ControlProcess" as part of the message sequence sent resulting from theoperator selecting either the complete row indication or selecting theshut down option. Message "L" is received from the condition monitoringand control process and this message is sent on the basis of an alarmcondition or malfunction and requests the "Row Spray Control Process" toclose all valves.

FIG. 14 details the functions of the "Condition Monitoring & ControlProcess". Upon initialisation of the spraying system this process entersan initialisation and default parameter setup stage. Upon completion ofthis stage the process executes two separate independent sub-processeswhich operate concurrently. Sub-process 1 acts to receive inputs fromthe "Operator Control Process" designated by "H" wherein the operatorcan send messages to the "Condition Monitoring & Control Process" toeither set or release a manual override of an alarm condition. If theoperator wishes to set the manual override for an alarm the "Set toManual Override Status" function is executed wherein a message is sentto sub-process 2 indicating the particular alarm for which the operatorwishes to activate the manual override. However, if the operator wishesto release a previously set override, the process then executes the"De-activate Alarm" function which will de-activate the alarm condition.The "De-activate Alarm" function sends a message to the "OperatorControl Process" to indicate the alarm de-activation. Sub-process 2 actsto receive alarm inputs from external sensors and messages fromsub-process 1 and to process these inputs accordingly. In the preferredembodiment alarm condition sensors are provided for sensing fan motorcurrent, collision of the spraying subassemblies with an object,alternator temperature, engine speed, spraying pump speed, sprayingpressure and emergency stop. If a sensor input is out of a predeterminedsafe operating range as determined by the received external sensor inputand a manual override has not been set for this alarm, then execution ofthe sub-process proceeds along the path designated "out of range (manualoverride released)" wherein the "Activate Alarm" function is executed.Upon execution of this function, messages are sent to the "OperatorControl Process" to alert the operator, the "Fan Motor Control Process"to perform a shutdown of the fan motors and the "Row Spray ControlProcess" to close the row valves and halt the flow of fluid to the sprayheads. Alternatively, if a manual override has been set for theparticular alarm, then the alarm condition is not processed. If anexternal sensor subsequently indicates that a measured parameter is nowwithin its predetermined operating range, then execution proceeds alongthe path designated "in range" and the "De-activate Alarm" function isexecuted. As for sub-process1, upon execution of this function, amessage is sent to the "Operator Control Process".

I claim:
 1. A method spraying a growing plant having a foliage canopycomprising:a) operating two lower fans on a mobile frame situatedgenerally below said canopy to direct sprays entrained in two lower airstreams created by said lower fans to converge upwardly into a localitywithin said canopy from opposite sides thereof with sufficient energy todisplace at least some leaves from within said canopy in upward andoutward directions and expand said canopy; b) operating two upper fansalso on said frame situated generally above said canopy to direct sprayentrained in upper airstreams created by said upper fans to convergedownwardly over, into and partly through said canopy from the oppositesides therefor to co-act with said upwardly directed airstreams at saidlocality within said canopy and thereby create turbulence both withinsaid locality and around said canopy; c) operating a single fan also onsaid frame located above said canopy and rearwardly of said lower andupper fans to direct spray downwardly into said canopy to ensure furthercontinued turbulence, and d) transporting said frame past said plantduring said spraying operation.
 2. A method according to claim 1,wherein said mobile frame is a bridge, and said lower and upper fans arearranged in three separate spraying sub-assemblies mounted on respectiveframes which are themselves mounted on said bridge;comprising mountingsaid bridge intermediate its ends on an over row tractor, locating acentral one of said spraying sub-assemblies centrally with respect tothe over the row tractor and the other two of said spraying assemblieslaterally spaced therefrom, one on each side of said centralsub-assembly, and spraying canopies of three separate rows of plantssimultaneously while driving said tractor over a central row of thethree rows.
 3. Spray apparatus for spraying a row of crops of plantshaving a foliage canopy, comprising:a mobile frame; a sprayingsub-assembly having a pair of spaced arms carried by and depending fromsaid mobile frame, two lower fan spray heads, fastening means fasteningsaid lower fan spray heads with respect to lower ends of said spacedarms adjustable for both position and direction of spray when issuingfrom said fan spray heads, wherein said spaced arms are curved todiverge downwardly away from each other at their upper ends and convergedownwardly towards each other at their lower ends to define a horseshoeshape, and wherein there are two upper fan spray heads, said fasteningmeans securing said upper fan spray heads to the upper portions ofrespective said arms and the lower fan spray heads to the lower ends ofrespective said arms, and wherein said spraying sub-assembly furtherincludes a central further upper fan spray head, said further upper fanspray head being mounted on said mobile frame centrally above the saidcanopy and rearwardly of said upper and lower spray heads.
 4. Sprayapparatus as defined in claim 1, wherein the arms are curved to divergedownwardly away from each other at their upper ends, and to convergedownwardly towards each other at their lower ends.
 5. Spray apparatusaccording to claim 1 and including fastening means to adjustably securesaid fan spray heads to said arms both for position on said arms anddirection about a first axis, said fan spray heads each comprising amotor, fan and spray nozzle assembly, a swivel between said fasteningmeans and said motor, fan and spray nozzle assembly providing a secondadjustment means for direction about a second axis at right angles tothe first axis.
 6. Spray apparatus according to claim 5 and including apiston/cylinder assembly for providing adjustment means co-actingbetween said fastening means and said fan, motor spray nozzle assemblyfor effecting direction control of said second adjustment means. 7.Spraying apparatus according to claim 3, wherein said mobile framecomprises frame members, and attachment means for attaching said frameto a vehicle.
 8. Spray apparatus according to claim 3, wherein saidmobile frame is elongate, and comprises attachment means for attachingsaid elongate frame transversely to an over row tractor, there being apair of guides extending towards the center of said elongate frame fromits ends, a pair of slides slidable along respective said guides,piston/cylinder assemblies co-acting between respective said slides andsaid elongate frame to control positions of said slides,three suspensionmeans on said frame, and intermediate of said three suspension meansbeing central and fast with said frame, the other two said suspensionmeans being carried by respective said slides, and three said sprayingsub-assemblies suspended from respective said suspension means.
 9. Sprayapparatus according to claim 8, further comprising a bearing at theupper end of each said arm journalling said arm to be suspended,movement from said suspension means such that, upon collision with anobject, said arm can swivel upwardly and rearwardly.
 10. Spray apparatusaccording to claim 8, wherein each said suspension means comprises agenerally vertically oriented tilt control piston/cylinder assembly,pivot means supporting the upper end of each respective said arm of eachsaid sub-assembly to a respective said suspension means, each said armhaving an extension lug extending beyond its upper end, a link joiningextension lugs of adjacent upper arm ends of each respective saidsub-assembly,each said tilt control piston/cylinder assembly co-actingbetween a said suspension means and a said extension lug, theconfiguration being such that actuation of a said tilt controlpiston/cylinder controls tilt of said extension lugs to which it isconnected and thereby the space between said arms.
 11. Spray apparatusaccording to claim 10, further comprising an electronic control means,electrically actuated control means for each said generally verticallyoriented tilt control piston/cylinder and foliage canopy sensingtransducer,wherein said foliage canopy sensing transducer is affixed tosaid mobile frame providing varying electrical signals according to thedistance between said sensing transducer and said foliage canopy, saidsensing transducer being electrically coupled to said electronic controlmeans which in turn receives said varying electrical signals from saidsensing transducer and provides appropriate electrical signals to saidelectrically actuated control means of each tilt controlpiston/cylinder, each said electrically actuated control means beingelectrically coupled to said electronic control means, to effectadjustment of said space between said arms in accordance with sensedfoliage canopy size.
 12. Spray apparatus according to claim 11, whereinsaid electronic control means comprises a programmable logic controller.13. Spray apparatus according to claim 11, wherein said electricallycontrolled flow rate means comprises an electrically controlled pressureregulator.
 14. Spray apparatus according to claim 11, further comprisinga fluid pump, fluid flow transducers and electrically controlled flowrate means all in electrical communication with said electronic controlmeans, said fluid pump further being in fluid communication with saidspray heads and providing a flow of fluid from a fluid storage tank tosaid spray heads,wherein said electronic control means receiveselectrical signals from said fluid flow transducers and in combinationwith said received signals from said sensing transducer, providesappropriate electrical signals to said electrically controlled flow ratemeans to control the flow of said fluid from said storage tank to saidspray heads in accordance with said sensed foliage canopy size. 15.Spray apparatus according to claim 14, wherein said electronic controlmeans comprises a programmable logic controller.
 16. Spray apparatusaccording to claim 10, further comprising an electronic control means,electrically actuated control means for each said piston/cylinderassembly co-acting between respective said slides and said elongateframe and foliage canopy sensing transducer,wherein said foliage canopysensing transducer is affixed to said mobile frame providing varyingelectrical signals according to the distance between said sensingtransducer and said foliage canopy, said sensing transducer beingelectrically coupled to said electronic control means which in turnreceives said varying electrical signals from said sensing transducerand provides appropriate electrical signals to said electricallyactuated control means of each piston/cylinder assembly, each saidelectrically actuated control means being electrically coupled to saidelectronic control means, to effect adjustment of said slides.
 17. Sprayapparatus according to claim 16, wherein said electronic control meanscomprises a programmable logic controller.
 18. Spray apparatus accordingto claim 16, wherein said electrically controlled flow rate meanscomprises an electrically controlled pressure regulator.